1. Field of the Invention
The present invention relates to a surface discharge type plasma display panel (PDP).
An AC surface discharge type PDP is commercialized as a display device of a television set having a large screen. The surface discharge type has first and second display electrodes that are anodes and cathodes in display discharge for ensuring a luminance and are arranged in parallel on a front or a back substrate.
A xe2x80x9cthree-electrode structurexe2x80x9d that has address electrodes arranged so as to cross display electrode pairs is well known as an electrode matrix structure of the surface discharge type PDP. One electrode of the display electrode pair (a second display electrode) is used as a scanning electrode for row selection, and the address discharge is generated between the scanning electrode and the address electrode so as to control wall charge for addressing in accordance with contents of display. After the addressing, by applying a sustaining voltage having alternating polarity to the display electrode pair, a surface discharge occurs along a surface of a substrate only at cells having a predetermined quantity of the wall charge.
2. Description of the Prior Art
Conventionally, a surface discharge type PDP is used in which N plus one display electrodes are arranged at a constant pitch in an interlace display, where N is the number of rows of a screen.
FIG. 11 is a plan view showing a cell structure of a conventional PDP.
The display electrode Xz is a laminate of a banding transparent conductive film 41z extending straightly in the row direction and a metal film 42z having a small width for augmenting the conductivity. The metal film 42z is arranged at the middle of the transparent conductive film 41z in the column direction. In the same way, the display electrode Yz includes a transparent conductive film 41z and a metal film 42z . Total N+1 of display electrodes Xz and Yz are arranged alternately, and the neighboring display electrodes Xz and Yz make an electrode pair for generating surface discharge, so as to form a row of screen. Each of the display electrodes Xz, Yz except both ends of the arrangement relates to display of two rows (an odd row and an even row), while the display electrodes Xz, Yz at the both ends relate to display of one row.
A discharge space is divided in each column by partitions 29z, and one column space that is a discharge space of one column is continuous over all rows. A structure of an area defined by neighboring partitions 29z and neighboring metal films 42z is a discharge cell (a display element) Cz. The address electrode Az is arranged at the middle of the column space.
An example of a driving method is as follows. In both address periods of an odd field and an even field, a scan pulse is applied to each display electrode Yz sequentially. Then, a potential of the odd display electrode Xz and a potential of the even display electrode Xz are switched complimentarily at each application of the scan pulse, so that an address discharge is generated between the display electrodes at the row for display (e.g., at an odd row in an odd field). In the display period following the address period, a sustaining pulse is applied alternately to the display electrodes Xz and Yz of the row that are used for the display, and a sustaining pulse is applied to the display electrode Xz of the row that is not used for the display (e.g., an even row in an odd field) in the same timing as the display electrode Yz. Namely, potential changes in the pair of display electrodes in the row that are not used for the display are in phase. Thus, discharge interference between an odd row and an even row can be reduced.
There is a problem of the conventional PDP in that since the column space is continuous over the entire length of the screen in the column direction, a cross talk of discharge can be generated in wide area over a few rows or a few tens of rows. In the structure having display electrodes arranged at a constant pitch, a displaying row and a non-displaying row are determined only by controlling their electrode potential. Therefore, the cross talk can occur easily compared with the structure in which a pair of display electrodes is arranged for each row so that an electrode gap between rows can be sufficiently wide. In order to eliminate the cross talk, a mesh pattern or a waffle pattern of partition can be provided for separating the cells, but it reduces an electrode area that contributes the discharge, resulting in reduction of display luminance. Since a main portion of the scanning electrode (Yz) is covered with the partition, an addressing potential may rise and a delay of discharge may occur. In addition, since the interlace display uses odd rows and even rows in time sharing for light emission, the separation of the cell will cause non-overlap of light emission areas of the odd row and the even row, resulting in a conspicuous flicker due to the time sharing light emission.
The object of the present invention is to ensure a reliability of addressing, to reduce a flicker and to decrease the area of cross talk in the column direction so that a display fluctuation can be reduced.
According to the present invention, the discharge gas space is divided by the unit of two cells aligned in the column direction. A scanning electrode that is one electrode of the display electrode pair is not used, but the other display electrode is used for dividing in the column direction. Since the dividing unit has an area of two cells, the light emission area of the odd row can overlap the light emission area of the even row in the column direction, so that the flicker cannot be conspicuous. Even if a cross talk of the discharge occurs, the fluctuation of the display is little since the cross talk is limited to the area of two cells or the multiples of the area. Since the discharge between the scanning electrode and the address electrode is not disturbed by the partition, a stable addressing can b e performed.
According to the first aspect of the present invention, a plasma display panel (PDP) comprises plural sets of first and second display electrodes making an electrode pair for surface discharge of each row, being arranged so that one electrode is shared by two neighboring rows for display, plural address electrodes crossing the electrode pair in each column, the second display electrode being a scanning electrode for row selection, and one or more partitions for dividing a discharge gas space in the column direction and only in a position within the area where the first display electrode is arranged.
According to the second aspect of the present invention, the address electrode has a first area opposing to the first display electrode and a second area opposing to the second display electrode, and the second area is larger than the first area.
According to the third aspect of the present invention, each of the first and the second display electrodes includes a transparent conductive film for ensuring an electrode area and a metal film for reducing a resistance, and the address electrode has a first area opposing to the metal film of the first display electrode and a second area opposing to the metal film of the second display electrode, the second area being larger than the first area.
According to the fourth aspect of the present invention, the portion of the partition that divides the discharge gas space in the column direction is arranged at the middle of the first display electrode in the column direction.
According to the fifth aspect of the present invention, the shape of the first display electrode is different from the shape of the second display electrode so that discharge characteristics of cells are made uniform.
According to the sixth aspect of the present invention, an effective area of the first display electrode is different from an effective area of the second display electrode so that discharge characteristics of cells are made uniform.
According to the seventh aspect of the present invention, the portion of the partition that divides the discharge gas space in the column direction is formed so as to have a gap that makes the discharge gas space continuous in the column direction.
According to the eighth aspect of the present invention, the first display electrode includes plural conductors separated from each other in the column direction within a screen area.
According to the ninth aspect of the present invention, each of the first and the second display electrode includes a transparent conductive film for ensuring an electrode area and a metal film for reducing a resistance, and the portion of the partition that divides the discharge gas space in the column direction is formed so as to overlap the metal film of the first display electrode.
According to the tenth aspect of the present invention, the PDP has three kinds of cells corresponding to three kinds of light emission colors, and an effective area of at least one of the first and the second display electrodes is adjusted for each light emission color, so that relative luminance of the each color can be adjusted.